Laser welded studs of screw in?

[kuranaga]

in fact we are trying to solve a completely idiotic problem, a problem that has a solution since humans invented the screw. Just ask any plumber.

 

[sunshine_eggo]

@sunshine_eggo​

the contact is also made by the thread itself and the top surface of your busbar (via the screw head lower side).

Not worth considering since this is common among all methods. This is also lower conductivity due to stainless bolt and non-copper washer.

Even if you count it, it's simply better to have more surface area between the terminals and bus bar.

 

[kuranaga]

ps 4-8 Nm torque is far too low to make a good connection on these terminals. Especially between Al surfaces!

 

[sunshine_eggo]

View attachment 76894
Last picture on the right side => egg shaped

Ever heard of perspective? All of them are.

Do you have a point, or are you being petty and criticizing my "artwork" because you have nothing meaningful to contribute?

 

[Hedges]

you didnt understand!

the original terminals should be hex-shaped (instead of egg-shapped) and some 10mm taller, so you can hold the terminal with a wrench while tightening the screw

Yes, terminals you can restrain with a wrench would do it. Most we've seen were so low profile you can't even put a DMM probe on it to measure voltage drop across interface. Just a 1/4" tall square terminal should do it.

I would prefer a stronger material (e.g. stainless steel) clamping cell terminal to busbar. And suitable surface treatment. Maybe tin-plated aluminum terminals.

Even if you count it, it's simply better to have more surface area between the terminals and bus bar.

I still say it ain't surface area you need, it is clamping force. Only a few high spots actually make contact, and more area less pressure results in fewer spots contacting. Bolting mechanism that allows higher force achieves more contact points.

 

[kuranaga]

Yes, terminals you can restrain with a wrench would do it. Most we've seen were so low profile you can't even put a DMM probe on it to measure voltage drop across interface. Just a 1/4" tall square terminal should do it.

I would prefer a stronger material (e.g. stainless steel) clamping cell terminal to busbar. And suitable surface treatment. Maybe tin-plated aluminum terminals.



I still say it ain't surface area you need, it is clamping force. Only a few high spots actually make contact, and more area less pressure results in fewer spots contacting. Bolting mechanism that allows higher force achieves more contact points.

yes they are far too low profile. Should be standing up from the casing at least some 10mm. Then a flat wrench would work. Or as I say a 90° strip standing up then you hold the screw head from the other side and tighten the nut

 

[kuranaga]

Ever heard of perspective? All of them are.

Do you have a point, or are you being petty and criticizing my "artwork" because you have nothing meaningful to contribute?

both!

 

[sunshine_eggo]

I still say it ain't surface area you need, it is clamping force. Only a few high spots actually make contact, and more area less pressure results in fewer spots contacting. Bolting mechanism that allows higher force achieves more contact points.

So, 1 sq-in of surface area under 5000# of pressure is no better than 0.5 sq-in of surface area under 5000# of pressure?

There's a practical limit to clamping pressure. Above a certain force, there's vastly diminishing returns that rapidly approach zero.

 

[kuranaga]

I still say it ain't surface area you need, it is clamping force. Only a few high spots actually make contact, and more area less pressure results in fewer spots contacting. Bolting mechanism that allows higher force achieves more contact points.

Both! and you still need e.g. Wago Alu Plus paste if it is AL!

 

[sunshine_eggo]

both!

So, you feel the need to point out that circles appear as ellipses when viewed from an angle (something any reasonably intelligent person already knows), and my shitty artwork.

Awesome. You bring so much value to this discussion.

I'm going to assume you're not a total ass, and English is not your first language, so you just come across as one.

 

[kuranaga]

So, you feel the need to point out that circles appear as ellipses when viewed from an angle (something any reasonably intelligent person already knows), and my shitty artwork.

Awesome. You bring so much value to this discussion.

I'm going to assume you're not a total ass, and English is not your first language, so you just come across as one.

egg = circle! Can you hold any round shape with a wrench?

 

[Hedges]

"Just ask any plumber."

 

[TWNomadin]

that thing seems still to be some "add on" on top of the original terminal with screw hole. I would not trust the connection between the two.

Best would be as I say a strip of thick aluminum with 1-2 lateral holes standing up and made from one piece of aluminum with the base.

Eve said it's in place of the the threaded female post not an add on like the stud is.
But I agree, a post like battle born has would be ideal. But I guess, at what point is the clamping pressure applied by the bolt/nut on to the bussbar against the post is enough and anything past that doesn't matter? Eve has mentioned the stud should not be torqued past 10nm.

 

[time2roll]

Not worth considering since this is common among all methods. This is also lower conductivity due to stainless bolt and non-copper washer.

Even if you count it, it's simply better to have more surface area between the terminals and bus bar.

My screws are aluminum, no washer.

 

[kuranaga]

"Just ask any plumber."



View attachment 76895

wont grab it.

 

[kuranaga]

But I agree, a post like battle born has would be ideal.

because Battleborn = clue.

Sometimes I really ask myself if many of these chinese manufacturers ever test their products. I assume in practice most of these batteries go into some pack production and finally are anyways welded, but not connected using any screws. So shitty terminals doesnt matter to them

 

[TWNomadin]

because Battleborn = clue.

Sometimes I really ask myself if many of these chinese manufacturers ever test their products. I assume in practice most of these batteries go into some pack production and finally are anyways welded, but not connected using any screws. So shitty terminals doesnt matter to them

Ya, I am sure most of these type of cells are going into packs that have everything welded together to eliminate assembly errors and longevity where the cells fail before the connections.